The place decides

Before I talk about inches, brightness or playback devices, I walk the route your customer takes: from the door to the counter, from the counter to the till, and out. A screen does not belong where a wall happens to be free, but where people are looking anyway.

The still points are the most valuable thing about a location, because people who wait, read. In the gyms on our advertising network, the strongest surfaces are not in the training room but where people queue or get changed. Also check the sight line from a distance: does the passer-by see the screen from the street, or only halfway into the shop?

Mounted too high is the most common mistake we come across, and it has two causes: down below the wall is taken, and up high it looks more impressive. But a screen above head height demands a movement nobody makes when attention lasts two seconds.

If a unit has to go higher because of doors or escape routes, tilt it downwards; five to ten degrees is enough and also helps against ceiling reflections. Think about the horizontal viewing angle too: many cheap panels already look washed out and colour-shifted at thirty degrees. If your audience walks past rather than standing in front, that counts for more than any resolution.

The question «what size do I need?» is really the question «from what distance should this be read?» What matters is not the diagonal but the letter height on the finished image. As a rule of thumb I calculate: letter height in millimetres equals viewing distance in metres times eight.

The third column applies to a normal layout of headline, short line and image. If you want to show a menu with many items, you need more surface or fewer items per image. Squeezing everything onto a 43-inch screen always ends the same way: the type gets small and nobody reads it. How content stays readable in two seconds is covered in the chapter on design.

Light is what gets underestimated most often, because it changes over the day. Anyone measuring on a Tuesday morning under an overcast sky does not see what happens on Friday at four, when the sun comes in low through the glass front.

The most effective countermeasure costs almost nothing: move a light fitting or aim a spot differently. Which brightness class suits which location is covered in the chapter on technology.

Format is usually decided by instinct: portrait supposedly looks more modern, landscape is the normal thing. Neither is an argument. What decides it is the content you want to show over the coming years.

Portrait works when people are walking past and the content stacks up: individual offers, people, products, dates, directions. It works where the wall is narrow – a pillar, a niche, beside the door – and takes vertically filmed video without bars.

Landscape works for moving images, menu boards with several columns, occupancy plans and everything that sits side by side for comparison. In meeting rooms and hotel lobbies it is almost always right, because a laptop gets plugged in there now and then.

Two things matter more than the decision itself. First: stick with it – an installation of three portrait and two landscape screens doubles the design work for ever. Second: a consumer television must not simply be turned on its side. Continuous operation in portrait needs an approved device, otherwise heat builds up inside the housing.

The shop window is the most tempting spot and the most demanding. Behind glass the unit sits in a small greenhouse: the sun heats the pane, the air behind it stands still, and an ordinary display eventually switches into thermal protection – usually on the afternoon when the most people are walking past.

Think about the back: from inside, customers would otherwise see a black surface with cables. And clarify early whether the landlord or the municipality has a say on illuminated signage – in old town locations that is the rule.

Outdoors, different laws apply. An outdoor unit is not an indoor unit with a roof but a construction of its own – which is why it is worth asking whether a shop window from the inside serves the same purpose.

Cold is as much an issue as heat: good outdoor units warm themselves up before starting, so the panel does not become sluggish below freezing.

A site visit rarely takes more than an hour and saves half days later. We come with a lux meter, tape measure, ladder and camera – and if possible at a busy time of day, not on a quiet Monday morning.

This list answers three things: device, bracket, connection. Fill it in before ordering and you will drill exactly once.